IMO 2018 Shortlist G4
A point T is hosen inside a triangle ABC. Let A1, B1, and C1 be the re e tions of T in BC, CA, and AB, respe tively. Let...
Category: Geometry
Problem
A point T is hosen inside a triangle ABC. Let A1, B1, and C1 be the re e tions of T in BC, CA, and AB, respe tively. Let Ω be the ir um ir le of the triangle A1B1C1. The lines A1T, B1T, and C1T meet Ω again at A2, B2, and C2, respe tively. Prove that the lines AA2, BB2, and CC2 are on urrent on Ω. (Mongolia)